My understanding is that the space guys theorized there had been water on Mars at some time, but they didn’t know if any remained. This is the first time they’ve actually found any. Or, at least they’re pretty sure what they found was water. They can’t retrieve it and test it in the lab.

I recall that people have seen what looked like polar ice caps on Mars at various times through their telescopes, but to actually 1) find it/touch it, and 2) confirm that it’s H20 and not something else is pretty amazing.

I am, and I have been interested in Mars for a long time, and while this is news, it is not that huge. We’ve known that Mars has had water ice since Viking, and Mars Express has mapped its near surface extent – see, e.g.,